From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755556Ab3LSSgN (ORCPT ); Thu, 19 Dec 2013 13:36:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:20158 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753698Ab3LSSgM (ORCPT ); Thu, 19 Dec 2013 13:36:12 -0500 Message-ID: <52B33C93.2020006@redhat.com> Date: Thu, 19 Dec 2013 13:36:03 -0500 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Mel Gorman , Andrew Morton CC: Alex Thorlton , Sasha Levin , Linux-MM , LKML Subject: Re: [PATCH] mm: Remove bogus warning in copy_huge_pmd References: <1386690695-27380-1-git-send-email-mgorman@suse.de> <1386690695-27380-11-git-send-email-mgorman@suse.de> <52B0D5F9.5030208@oracle.com> <20131219120007.GJ11295@suse.de> In-Reply-To: <20131219120007.GJ11295@suse.de> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/19/2013 07:00 AM, Mel Gorman wrote: > Sasha Levin reported the following warning being triggered > > [ 1704.594807] WARNING: CPU: 28 PID: 35287 at mm/huge_memory.c:887 copy_huge_pmd+0x145/ 0x3a0() > [ 1704.597258] Modules linked in: > [ 1704.597844] CPU: 28 PID: 35287 Comm: trinity-main Tainted: G W 3.13.0-rc4-next-20131217-sasha-00013-ga878504-dirty #4149 > [ 1704.599924] 0000000000000377e delta! pid slot 27 [36258]: old:2 now:537927697 diff: 537927695 ffff8803593ddb90 ffffffff8439501c ffffffff854722c1 > [ 1704.604846] 0000000000000000 ffff8803593ddbd0 ffffffff8112f8ac ffff8803593ddbe0 > [ 1704.606391] ffff88034bc137f0 ffff880e41677000 8000000b47c009e4 ffff88034a638000 > [ 1704.608008] Call Trace: > [ 1704.608511] [] dump_stack+0x52/0x7f > [ 1704.609699] [] warn_slowpath_common+0x8c/0xc0 > [ 1704.612617] [] warn_slowpath_null+0x1a/0x20 > [ 1704.614043] [] copy_huge_pmd+0x145/0x3a0 > [ 1704.615587] [] copy_page_range+0x3f2/0x560 > [ 1704.616869] [] ? rwsem_wake+0x51/0x70 > [ 1704.617942] [] dup_mmap+0x2c9/0x3d0 > [ 1704.619146] [] dup_mm+0xad/0x150 > [ 1704.620051] [] copy_process+0xa68/0x12e0 > [ 1704.622976] [] ? __lock_release+0x1da/0x1f0 > [ 1704.624234] [] do_fork+0x96/0x270 > [ 1704.624975] [] ? context_tracking_user_exit+0x195/0x1d0 > [ 1704.626427] [] ? trace_hardirqs_on+0xd/0x10 > [ 1704.627681] [] SyS_clone+0x16/0x20 > [ 1704.628833] [] stub_clone+0x69/0x90 > [ 1704.629672] [] ? tracesys+0xdd/0xe2 > > This warning was introduced by "mm: numa: Avoid unnecessary disruption > of NUMA hinting during migration" for paranoia reasons but the warning > is bogus. I was thinking of parallel races between NUMA hinting faults > and forks but this warning would also be triggered by a parallel reclaim > splitting a THP during a fork. Remote the bogus warning. > > Signed-off-by: Mel Gorman Acked-by: Rik van Riel